Re: Bali, Indonesia.
If you wanna flyfish in Bali, especially saltwater, that all depends on the weather & season (unfortunately now is not the best season).
Your best bet might be hitting the mahi-mahi/dorado/dolphin fish (or locally called 'lemadang')
As far as I know there's only one local fly fisher in Bali (I know him well personally) but if you're open for option and willing to spend the bucks go with Adhek Amarta for popping, he's one of the best popping angler/guides in the world (he also produces high end popper lures that catered for the high end Japanese market).
He's the most sought after guide for popping especially for professional Japanese anglers and has been featured in many fishing videos.
Hope that helps a bit, cheers from Indo